The present invention relates generally to marking devices and methods for land surveying and building construction. More particularly, the device and method of the invention utilizes a remote-controlled mirror device to deflect the line of sight or beam pathways of leveling devices. That in turn allows easier and safer transfer of the axis lines of a multi-story building under construction from one floor to the next as well as over any other obstacles to a direct line of sight.
During the building construction, the main objective of the operator is to mark down the axis lines of the future building. This step of layout is typically conducted before the actual excavation and building construction begins. Various well-defined objects are used as basis for the markings such as existing nearby buildings, previously marked property lines, etc.
It is a common practice to layout the axis lines of the building outside the actual construction zone so as to preserve them from disturbance during the actual work. First, the lower walls of the nearby buildings or nearby paved roads or pedestrian walks are used to place the initial marks. Then, a first set of horizontal axis lines A is established by connecting these initial marks, see FIG. 1. Finally, the second set of horizontal marks B perpendicular to the first set A is established by using the first set A as a base as well as another building or a well-defined object if available. Therefore the entire set of horizontal markings and lines is available as a reference system for subsequent positioning the corners, pillars, foundation borders and other elements of the future building. FIG. 1 shows the position of the future column K at the intersection of the axis lines A and B.
It is critical to be as precise as possible during this initial layout operation as well as subsequent layout of various floors of the building. Typically, the maximum deviation allowed is not more than plus or minus one eighth to one quarter of an inch.
Building construction and land surveying devices are well known in the prior art. One such typical instrument is an odolite also known as theodolite, which is used in the field to obtain precise angular and distance measurements for highway construction, industrial plant layout, tunnel construction and alignment, and other civil engineering work. Other known instruments, such as the Electronic Distance Measuring (EDM) Device may be used to determine the distance between the instrument and any randomly located field point or survey station within its effective range. In working with the known instruments in land surveying operations, it is necessary for both the instrument station and the random field location to be manned by one or more members of the survey crew. In a known manner, the crew is able to manually align the instrument with the field location so that the various required angular and linear measurements may be made. It is apparent that this alignment procedure is time-consuming and requires the combined effort of several different individuals at different locations in the area to be surveyed.
The following United States patents illustrate the state of the art in surveying instruments; U.S. Pat. No. 3,653,774 (La Roche); U.S. Pat. No. 3,469,919 (Zellner); U.S. Pat. No. 4,107,530 (Brumfield et al); U.S. Pat. No. 4,425,043 (Van Rosmalen); U.S. Pat. No. 2,836,894 (Wagner); U.S. Pat. No. 3,580,687 (Hansen); U.S. Pat. No. 4,279,036 (Pfund); U.S. Pat. No. 4,466,189 (Tobin, Jr.); U.S. Pat. No. 4,457,621 (Harris et al); U.S. Pat. No. 4,470,698 (Green, Jr. et al); and U.S. Pat. No. 3,989,942 (Waddoups).
The LaRoche patent (U.S. Pat. No. 3,653,774) discloses a theodolite including a servo-motor used for tracking a moving target. It does not disclose on-command alignment in a land surveying procedure. The Zelner patent (U.S. Pat. No. 3,469,919) discloses an electronic surveying instrument including a laser beam projector coupled with an angled mirror to produce horizontal datum. The disclosed device also includes a receiver for receiving reflected beams to detect a datum plane and a pair of adjustable antennas which are movable to an elevation intersecting the datum plane and adjustable to insure proper spacing and elevation of the antennas.
The Wagner patent (U.S. Pat. No. 2,836,894) discloses a theodolite useful for tracking moving objects. It does not disclose a remotely controlled land surveying assist device for aligning on-command the same with a remote field location. The Hansen patent (U.S. Pat. No. 3,580,687) discloses a surveying instrument, which detects when it is misaligned, but it provides no means for on-command alignment.
The Pfund patent (U.S. Pat. No. 4,279,036) discloses a communication system with mobile vehicles including the use of a satellite; the Tobin, Jr., patent (U.S. Pat. No. 4,466,189) discloses an optical sensor used as a navigation aid for fixing and maintaining an accurate site on a target during rough water conditions; the Harris et al patent (U.S. Pat. No. 4,457,621) discloses a surveillance system including a laser range finder for use in conjunction with a passive surveillance scanner; and the Green, Jr., et al patent (U.S. Pat. No. 4,470,698) discloses a scanning and/or tracking mechanism for use as part of either an optical obstacle avoidance or target tracking airborne radar set. It is apparent that none of the last four mentioned patents disclose instruments useful for land surveying operations.
The Webb patent (U.S. Pat. No. 4,907,879) provides a remote-controlled land surveying assist device capable of aligning the path of the beam horizontally as directed by an operator from a remote location. Alignment is achieved when the incoming beam is reflected back towards the source thereof. It does not have the capability to change the beam pathway vertically in a useful way as described in detail below.
The LASEROPTRONIX Company (Stockholm, Sweden) markets the device called GUIDER 1-40 as described on the web site of the company, www.laseroptronix.se. This device incorporates a mirror hanging in a self-aligning holder. The holder is equipped with a plumb and that makes the mirror always vertically oriented.
Finally, the Piske patent (U.S. Pat. No. 5,331,395) describes an instrument for aligning a laser-leveling device along a building line by swinging the head of the instrument containing a rotating prism.
The term “theodolite” is used throughout this description to include broadly various surveying optical devices as well as sources of light beams such as laser etc. In a typical theodolite 60 (see FIG. 4), one of the main elements is an optical telescope 70, capable of swinging in a horizontal and vertical planes. It is also equipped with a vertical optical plumb 65 aligned with the vertical axis of the telescope. Manually operated plumbs are used by the operators or members of the surveying crew to transfer the axis lines from one floor of the building to the next.
As the building construction progresses, the axis lines are first transferred from the surface into the excavated area for layout of the foundation of the building, then to the first floor, then to the second floor as these floors are erected and so on. Typically, two operators conduct such transfer. The first operator 50, also referred to as an instrument man, is located at the ground surface and uses the theodolite 60, as shown on FIG. 2B. The second operator 80, also referred to as a rod man, is standing at the top existing floor 10 of the building and holds vertically the plumb 85. The instrument man 50 positions the theodolite 60 on the base axis line, aligns it vertically by using the internal optical plumb and then observes the rod man 80 with the plumb 85. The instrument man 50 advises the rod man 80 (verbally or by radio) as to how the rod man 80 shall move such that the plumb 85 is aligned with the axis line on the ground as can be observed through the telescope of the theodolite 60. Once that is achieved, the rod man 80 is advised to place a mark on the floor to indicate the proper position of the new axis line. The same procedure is then repeated from the other side of the building and the second mark is placed on the floor. The two marks are then connected to form a new axis line. Other axis lines are transferred in a similar manner. Intersections of axis lines mark the places for main pillars of the building. Once the construction of the floor is finished, the same procedure is repeated again to layout the next floor of the building.
This method of transferring the reference lines from the ground to the next floor under construction is sufficient for buildings having a maximum of 10–12 floors. For buildings of greater height this method is not practical and may present significant errors because of the following limitations:                the theodolite scope has to be risen too steeply for upper floors of the building, which increases the tilt error of the instrument to an unacceptable value;        the distance between the instrument man and the rod man gets to be too great to the point that the instrument man can hardly see the plumb bob string;        the natural swing of the building becomes too high. For a 30–40 floor building, the swing can be as high as a one-half to ⅜ inches, and can be further increased by wind factor and working cranes; and        the scope reticals projected on the site are to be scaled into ¼ to ½ inch.        
It would be therefore desirable to have a reliable method to transferring the axis lines from one floor to the next with optional reference to the common control (so as to verify accuracy) for all buildings including high-risers.
Another problem with the traditional method is that both operators have to have a direct line of sight causing the rod man to stand too close to the edge of the building and creating a safety concern. It would be desirable not to have the direct line of sight and allow the rod man step back further inside the building during the layout procedure so as to improve the safety of construction process.
None of the known devices and methods of the prior art allow for these objectives to be achieved. The need exists therefore for a device and method allowing the transfer of the axis lines from one floor to the next floor of the building under construction as well as to allow the rod man to remain far enough from the edge of the floor to improve his safety. The need also exists generally for a device allowing the transfer of a desired point of reference to another point of reference when there is no direct line of sight between the two points, such as when there is an obstacle of some sort or a non-transparent object, which cannot be moved easily out of the way.